Is anybody else's kid just learning so fast suddenly?

We've been teaching sign language since 3 months. From around 6 or 7 months he could sign "milk". A couple months after he started signing "change". It was like that for so long. Just saying mama and dada and the two signs.

Then a month and a half ago he started picking up a couple more signs. And now? This last week it's been a new sign every day! I didn't think things would just snowball like this.